Jason and Spencer do have the same biological father, who is Peter Hastings. However, there is some complexity surrounding their parentage that I will explain in more detail.
Peter Hastings is married to Veronica Hastings, and they are the adoptive parents of Spencer. Spencer was born to Mary Drake, who is Peter’s ex-mistress and also Jessica DiLaurentis’ twin sister. Therefore, Peter is the biological father of both Jason and Spencer, but he only shares a legal and adoptive relationship with Spencer.
The situation becomes even more tangled when we consider that Jessica DiLaurentis is the mother of both Jason and Spencer. However, the identity of Spencer’s biological father was kept hidden for a long time. This secret was eventually revealed, and it was discovered that Peter is Spencer’s biological father.
The fact that Jason and Spencer share the same biological father, but have different biological mothers, adds another layer of complexity to their relationship. It also explains why Peter and Veronica chose to keep the truth about Jason’s parentage a secret from almost everyone.
It is worth noting that the Hastings family has been involved in numerous secrets and scandals throughout the television series. These secrets have caused tension and strained relationships within the family, particularly between Peter and his daughters, Spencer and Melissa.
Jason and Spencer do have the same biological father, Peter Hastings. However, due to the complicated circumstances surrounding their parentage, their relationship is not straightforward. The revelation of their shared parentage has caused significant upheaval and has had a lasting impact on the Hastings family dynamics.